Small changes make a hulking difference

If you know the comic book story of The Incredible Hulk, you already know a bit about why Panama TR4 can be so bad.

The story of the Hulk’s transformation from brilliant scientist to, as Marvel Comics says, “an incredible engine of destruction” features in the banana industry’s current series of TR4 workshops.

It’s one way the workshop team helps growers appreciate the seriousness of the plant disease – and how important it is to do everything possible to keep it off their farms.

As team member Stewart Lindsay says during one workshop, it’s the Hulkish and near-indestructible chlamydospores produced by the fungus Fusarium oxysporum that makes Panama disease so fearsome.

“For whatever important commercial crops you can think of there’s a Fusarium that attacks it,” Stewart says. “But they’re all separate and different – and what makes them a major disease issue is chlamydospores.”

In the case of banana plants, when first attacked they’re infected by potentially millions of the less damaging conidia spores. It’s the plant’s own actions to defend itself that ends up shutting down its vascular system leading to plant death and the triggering of chlamydospores. The same thing happens when an infected banana plant is cut down without using proper destruction methods.

“These things are incredibly robust,” Stewart says of the spores responsible for strains of Panama disease, including TR4. “They’re just about impossible to kill.”

The fungal spores’ survival skills include outlasting “very high temperatures for long periods, 30 years in the soil in the absence of any plants, these things can take up to three months in the bottom of a dam to drown”.

The function of the TR4 workshops, which are funded by $600,000 of Australian and Queensland Government funds, is to help banana growers understand the disease and to provide practical information on stopping it reaching their farms.

The workshops are held by TR4 Extension Project, led by Shane Dullahide, and have so far reached growers whose farms represent more than 70 per cent of the North Queensland production area.

The workshops are now reaching out to other growers to make sure as many as possible attend, the message being that efforts to contain TR4 are substantially strengthened when more growers participate.

“For all of us caught up in this, it’s such an overwhelming issue you kind of end up like a deer in the headlights,” Stewart tells growers.

“The only way to deal with what seems like an overwhelming issue is to deal with it one step at a time.”

The steps used at the workshops include growers being provided with maps of their farms and worksheets to help them identify possible entry points for the fungus and ways to block it.

“At the end of it you’ll have a better understanding of how the disease works and spreads, the disease pathways onto your farms, you will have begun thinking about a plan or have one drawn up and have a prioritisation of which things you’ll tackle first,” Stewart says.

Shane Dullahide speaks at workshops about issues including identifying and reporting suspect plants. At this workshop he advises what will happen if reporting doesn’t happen.

“The only way we’re going to contain this disease is if we catch it early,” Shane says.

“We’ve had plenty of people tell us at workshops that there’s a real issue with reporting a plant.

“If you ignore it, those chlamydospores are going to get in the soil, they’re going to be spread eventually to somewhere else. It’s going to be a time bomb down the track for your farm, eventually it’s going to be in your neighbours’ farms and eventually it’s going to be everywhere downstream.”

The workshops also discuss how TR4 is carried.

“It’s important to understand all the pathways for TR4 to come onto your farm,” Australian Banana Growers’ Council officer Robert Mayers says.

Growers place transparencies over aerial maps of their farms to mark the points where TR4 vectors – plant material, soil and water – could enter.

The project leader of the banana industry’s National Banana Development and Extension Project, Tegan Kukulies, tells growers the key is to “exclude, exclude, exclude” any non-essential farm visits.

“Ask yourself this question, ‘in order to conduct your farm business and to keep your farm Panama-free does that person or item absolutely have to come onto my property?’

“If the answer’s ‘yes’ then that’s what this workshop module is about – how to get that person or equipment onto your farm in the safest possible manner.

“To grow and sell bananas you can’t exclude all movements onto and off your property but from the exclusion principle we come to the point where people are ‘coming clean and leaving clean’ on your property on your terms.”

Growers are encouraged to think of their farm as “clean” and everything else as “dirty”.

They are provided with information about how to establish zones on their farms to limit the potential of TR4 reaching the paddocks.

The workshops also inform growers about the decontamination and wash down processes and important basics like the proper management of footbaths.

There is information on the use of planting material and tips on fencing, including using feral pig-proof wire and ensuring property boundaries are surveyed before fencing work begins.

Many growers have already come up with their own innovations for decontamination, zones and managing drainage and the workshop is an excellent forum for exchanging ideas.

“It’s about changing the habits of a life-time,” Stewart says. “But in the scheme of things, they’re only small changes.”

And when growers are up against one of the world’s worst banana plant diseases – every change helps make a Hulk-sized difference.

Growers wanting information on the TR4 workshops should go to www.panama.org.au or phone 4064 1182